clockToPosix

pub fn clockToPosix(clock: Io.Clock) posix.clockid_t {
    return switch (clock) {
        .real => posix.CLOCK.REALTIME,
        .awake => switch (native_os) {
            .driverkit, .ios, .maccatalyst, .macos, .tvos, .visionos, .watchos => posix.CLOCK.UPTIME_RAW,
            else => posix.CLOCK.MONOTONIC,
        },
        .boot => switch (native_os) {
            .driverkit, .ios, .maccatalyst, .macos, .tvos, .visionos, .watchos => posix.CLOCK.MONOTONIC_RAW,
            // On freebsd derivatives, use MONOTONIC_FAST as currently there's
            // no precision tradeoff.
            .freebsd, .dragonfly => posix.CLOCK.MONOTONIC_FAST,
            // On linux, use BOOTTIME instead of MONOTONIC as it ticks while
            // suspended.
            .linux => posix.CLOCK.BOOTTIME,
            // On other posix systems, MONOTONIC is generally the fastest and
            // ticks while suspended.
            else => posix.CLOCK.MONOTONIC,
        },
        .cpu_process => posix.CLOCK.PROCESS_CPUTIME_ID,
        .cpu_thread => posix.CLOCK.THREAD_CPUTIME_ID,
    };
}